poles chapter 36 magnetism poles - iona physics magnetism.pdf · 1 apr 2812:32 pm chapter 36...
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Chapter 36 Magnetism
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Poles1. Every magnet has two poles.2. Opposite poles attract.3. Like poles repel.
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PolesYou cannot isolate a single pole.Cut a magnet and you have two magnets.
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Some substances can be made into permanent magnets.
Some substances become temporary magnets when placed in a magnetic field. (That is why a magnet can attract a nail which is not magnetized.)
Some substances are not magnetic. (Example: wood)
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Magnetic FieldAnother kind of field
-gravitational field acts on any mass-electrical field acts on any charge-magnetic field acts on a magnetic pole or moving charge.
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Magnetic DomainsA spinning electron is a tiny magnet. A pair of electrons spinning in OPPOSITE directions cancel each other out.
Electrons spinning in the SAME direction add up.
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What a field "looks like"Lines always point away from the North and toward the South
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A Compass needle points parallel to the "Lines of Force"
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An electrical current sets up a magnetic field.
This is a "relativistic effect" if you were moving along with the current carriers you would not observe any magnetic field.
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A magnetic field exerts a force on a moving charge. This is the principle behind all electrical meters and motors.
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Which of the magnets is/are reversed?
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